Aluminum alloy extruded material and electronic device housing comprising same

ABSTRACT

An aluminum alloy extruded material and an electronic device housing including the same are provided. The aluminum alloy extruded material includes aluminum, zinc, magnesium, and copper, and the amount of copper and the amount of zinc have a correlation.

CROSS-REFERENCE TO RELATED APPLICATION(S)

This application is a continuation application, claiming priority under§ 365(c), of an International application No. PCT/KR2022/011031, filedon Jul. 27, 2022, which is based on and claims the benefit of a Koreanpatent application number 10-2021-0101317, filed on Aug. 2, 2021, in theKorean Intellectual Property Office, and of a Korean patent applicationnumber 10-2022-0062924, filed on May 23, 2022, in the KoreanIntellectual Property Office, the disclosure of each of which isincorporated by reference herein in its entirety.

BACKGROUND 1. Field

The disclosure relates to an aluminum alloy extruded material and anelectronic device housing including the same.

2. Description of Related Art

An electronic device may be a device that performs a specific functionaccording to a loaded program, such as a home appliance, an electronicnote, a portable multimedia player, a mobile communication terminal, atablet personal computer (PC), a video/audio device, a desktop/laptopcomputer, a vehicle navigation system, and the like. For example, suchelectronic devices may output stored information as sound or images.Along with an increase in the integration level of electronic devicesand the increasing popularity of ultra-high-speed, large-capacitywireless communication, various functions have recently been loaded intoa single electronic device, such as a mobile communication terminal. Forexample, an entertainment function such as gaming, a multimedia functionsuch as music/video play, a communication and security function formobile banking, a scheduling function, and an electronic walletfunction, as well as a communication function, have been integrated intoa single electronic device.

An electronic device includes a housing that may be formed of variousmaterials, and the housing of the electronic device protects internalcomponents of the electronic device from an external impact. Inaddition, the housing of the electronic device may be manufactured suchthat the electronic device is easy for a user to carry and made to beaesthetically pleasing to the user. The housing of the electronic devicemay need to have high strength and hardness to protect various internalcomponents and modules of the electronic device, and may be excellent ingloss for the exterior quality.

As an electronic device housing, an alloy for aluminum extrusion may beused. An aluminum alloy may be excellent in rigidity and have a highgloss and/or glossy surface characteristic of a metal. However, sincethe rigidity and exterior quality conflict with each other, an aluminumalloy with high rigidity has low exterior quality and an aluminum alloywith improved exterior quality has low rigidity. Thus, it may bedifficult to use the above aluminum alloys in an electronic device.

The above information is presented as background information only toassist with an understanding of the disclosure. No determination hasbeen made, and no assertion is made, as to whether any of the abovemight be applicable as prior art with regard to the disclosure.

SUMMARY

Aspects of the disclosure are to address at least the above-mentionedproblems and/or disadvantages and to provide at least the advantagesdescribed below. Accordingly, an aspect of the disclosure is to providean alloy extruded material including aluminum and various metal elementsas an aluminum alloy extruded material.

Another aspect of the disclosure is to provide an aluminum alloyextruded material that is excellent in strength and hardness andadhesion of a surface oxide film while realizing a high gloss and/orglossy surface characteristic.

Additional aspects will be set forth in part in the description whichfollows and, in part, will be apparent from the description, or may belearned by practice of the presented embodiments.

In accordance with an aspect of the disclosure, an aluminum alloyextruded material is provided. The aluminum alloy extruded materialincludes aluminum, zinc, magnesium, and copper, and an amount of copperand an amount of zinc correlate.

In accordance with another aspect of the disclosure, an electronicdevice housing is provided. The electronic device housing includes analuminum alloy extruded material or is surrounded and formed by thealuminum alloy extruded material.

In accordance with another aspect of the disclosure, a method ofpreparing an aluminum alloy extruded material is provided. The methodincludes an operation of preparing an aluminum metal, an operation offorming an aluminum alloy by melting the aluminum metal and adding metalelements including zinc and magnesium, an operation of heating andextruding the aluminum alloy, and an operation of performing a heattreatment on the extruded aluminum alloy to form an aluminum alloyextruded material.

According to various embodiments, an alloy extruded material includingaluminum and various metal elements may be provided as an aluminum alloyextruded material.

According to various embodiments, an aluminum alloy extruded materialexcellent in strength and hardness and adhesion of a surface oxide filmwhile realizing a high gloss and/or glossy surface characteristic may beprovided.

Other aspects, advantages, and salient features of the disclosure willbecome apparent to those skilled in the art from the following detaileddescription, which, taken in conjunction with the annexed drawings,discloses various embodiments of the disclosure.

BRIEF DESCRIPTION OF THE DRAWINGS

The above and other aspects, features, and advantages of certainembodiments of the disclosure will be more apparent from the followingdescription taken in conjunction with the accompanying drawings, inwhich:

FIG. 1 is a block diagram illustrating an electronic device in a networkenvironment according to an embodiment of the disclosure;

FIG. 2 is a flowchart of operations of a method of preparing an aluminumalloy extruded material according to an embodiment of the disclosure;

FIG. 3 is a flowchart of a method of preparing an aluminum alloyextruded material according to an embodiment of the disclosure; and

FIG. 4 is an image obtained by capturing a cross section of an aluminumalloy extruded material according to an embodiment of the disclosure.

Throughout the drawings, it should be noted that like reference numbersare used to depict the same or similar elements, features, andstructures.

DETAILED DESCRIPTION

The following description with reference to the accompanying drawings isprovided to assist in a comprehensive understanding of variousembodiments of the disclosure as defined by the claims and theirequivalents. It includes various specific details to assist in thatunderstanding but these are to be regarded as merely exemplary.Accordingly, those of ordinary skill in the art will recognize thatvarious changes and modifications of the various embodiments describedherein can be made without departing from the scope and spirit of thedisclosure. In addition, descriptions of well-known functions andconstructions may be omitted for clarity and conciseness.

The terms and words used in the following description and claims are notlimited to the bibliographical meanings, but, are merely used by theinventor to enable a clear and consistent understanding of thedisclosure. Accordingly, it should be apparent to those skilled in theart that the following description of various embodiments of thedisclosure is provided for illustration purpose only and not for thepurpose of limiting the disclosure as defined by the appended claims andtheir equivalents.

It is to be understood that the singular forms “a,” “an,” and “the”include plural referents unless the context clearly dictates otherwise.Thus, for example, reference to “a component surface” includes referenceto one or more of such surfaces.

FIG. 1 is a block diagram illustrating an electronic device in a networkenvironment according to an embodiment of the disclosure.

Referring to FIG. 1 , an electronic device 101 in a network environment100 may communicate with an electronic device 102 via a first network198 (e.g., a short-range wireless communication network), or communicatewith at least one of an electronic device 104 or a server 108 via asecond network 199 (e.g., a long-range wireless communication network).According to an embodiment, the electronic device 101 may communicatewith the electronic device 104 via the server 108. According to anembodiment, the electronic device 101 may include a processor 120, amemory 130, an input module 150, a sound output module 155, a displaymodule 160, an audio module 170, a sensor module 176, an interface 177,a connecting terminal 178, a haptic module 179, a camera module 180, apower management module 188, a battery 189, a communication module 190,a subscriber identification module (SIM) 196, or an antenna module 197.In some embodiments, at least one (e.g., the connecting terminal 178) ofthe above components may be omitted from the electronic device 101, orone or more other components may be added to the electronic device 101.In some embodiments, some (e.g., the sensor module 176, the cameramodule 180, or the antenna module 197) of the components may beintegrated as a single component (e.g., the display module 160).

The processor 120 may execute, for example, software (e.g., a program140) to control at least one other component (e.g., a hardware orsoftware component) of the electronic device 101 connected to theprocessor 120, and may perform various data processing or computation.According to an embodiment, as at least a part of data processing orcomputation, the processor 120 may store a command or data received fromanother component (e.g., the sensor module 176 or the communicationmodule 190) in a volatile memory 132, process the command or the datastored in the volatile memory 132, and store resulting data in anon-volatile memory 134. According to an embodiment, the processor 120may include a main processor 121 (e.g., a central processing unit (CPU)or an application processor (AP)), or an auxiliary processor 123 (e.g.,a graphics processing unit (GPU), a neural processing unit (NPU), animage signal processor (ISP), a sensor hub processor, or a communicationprocessor (CP)) that is operable independently from, or in conjunctionwith the main processor 121. For example, when the electronic device 101includes the main processor 121 and the auxiliary processor 123, theauxiliary processor 123 may be adapted to consume less power than themain processor 121 or to be specific to a specified function. Theauxiliary processor 123 may be implemented as separate from, or as partof the main processor 121.

The auxiliary processor 123 may control at least some of functions orstates related to at least one (e.g., the display module 160, the sensormodule 176, or the communication module 190) of the components of theelectronic device 101, instead of the main processor 121 while the mainprocessor 121 is in an inactive (e.g., sleep) state, or together withthe main processor 121 while the main processor 121 is in an activestate (e.g., executing an application). According to an embodiment, theauxiliary processor 123 (e.g., an ISP or a CP) may be implemented as aportion of another component (e.g., the camera module 180 or thecommunication module 190) that is functionally related to the auxiliaryprocessor 123. According to an embodiment, the auxiliary processor 123(e.g., an NPU) may include a hardware structure specified for artificialintelligence model processing. An artificial intelligence model may begenerated by machine learning. Such learning may be performed, forexample, by the electronic device 101 in which an artificialintelligence model is executed, or via a separate server (e.g., theserver 108). Learning algorithms may include, but are not limited to,for example, supervised learning, unsupervised learning, semi-supervisedlearning, or reinforcement learning. The artificial intelligence modelmay include a plurality of artificial neural network layers. Anartificial neural network may include, for example, a deep neuralnetwork (DNN), a convolutional neural network (CNN), a recurrent neuralnetwork (RNN), a restricted Boltzmann machine (RBM), a deep beliefnetwork (DBN), a bidirectional recurrent deep neural network (BRDNN), adeep Q-network, or a combination of two or more thereof, but is notlimited thereto. The artificial intelligence model may additionally oralternatively include a software structure other than the hardwarestructure.

The memory 130 may store various pieces of data used by at least onecomponent (e.g., the processor 120 or the sensor module 176) of theelectronic device 101. The various pieces of data may include, forexample, software (e.g., the program 140) and input data or output datafor a command related thereto. The memory 130 may include the volatilememory 132 or the non-volatile memory 134.

The program 140 may be stored as software in the memory 130 and mayinclude, for example, an operating system (OS) 142, middleware 144, oran application 146.

The input module 150 may receive a command or data to be used by anothercomponent (e.g., the processor 120) of the electronic device 101, fromthe outside (e.g., a user) of the electronic device 101. The inputmodule 150 may include, for example, a microphone, a mouse, a keyboard,a key (e.g., a button), or a digital pen (e.g., a stylus pen).

The sound output module 155 may output a sound signal to the outside ofthe electronic device 101. The sound output module 155 may include, forexample, a speaker or a receiver. The speaker may be used for generalpurposes, such as playing multimedia or playing record. The receiver maybe used to receive an incoming call. According to an embodiment, thereceiver may be implemented as separate from, or as part of the speaker.

The display module 160 may visually provide information to the outside(e.g., a user) of the electronic device 101. The display module 160 mayinclude, for example, a display, a hologram device, or a projector andcontrol circuitry to control a corresponding one of the display,hologram device, and projector. According to an embodiment, the displaymodule 160 may include a touch sensor adapted to sense a touch, or apressure sensor adapted to measure the intensity of force incurred bythe touch.

The audio module 170 may convert a sound into an electrical signal orvice versa. According to an embodiment, the audio module 170 may obtainthe sound via the input module 150 or output the sound via the soundoutput module 155 or an external electronic device (e.g., the electronicdevice 102 such as a speaker or headphones) directly or wirelesslyconnected to the electronic device 101.

The sensor module 176 may detect an operational state (e.g., power ortemperature) of the electronic device 101 or an environmental state(e.g., a state of a user) external to the electronic device 101, andgenerate an electrical signal or data value corresponding to thedetected state. According to an embodiment, the sensor module 176 mayinclude, for example, a gesture sensor, a gyro sensor, an atmosphericpressure sensor, a magnetic sensor, an acceleration sensor, a gripsensor, a proximity sensor, a color sensor, an infrared (IR) sensor, abiometric sensor, a temperature sensor, a humidity sensor, or anilluminance sensor.

The interface 177 may support one or more specified protocols to be usedfor the electronic device 101 to be coupled with the external electronicdevice (e.g., the electronic device 102) directly (e.g., by wire) orwirelessly. According to an embodiment, the interface 177 may include,for example, a high-definition multimedia interface (HDMI), a universalserial bus (USB) interface, a secure digital (SD) card interface, or anaudio interface.

The connecting terminal 178 may include a connector via which theelectronic device 101 may be physically connected to the externalelectronic device (e.g., the electronic device 102). According to anembodiment, the connecting terminal 178 may include, for example, anHDMI connector, a USB connector, an SD card connector, or an audioconnector (e.g., a headphone connector).

The haptic module 179 may convert an electrical signal into a mechanicalstimulus (e.g., a vibration or a movement) or an electrical stimuluswhich may be recognized by a user via his or her tactile sensation orkinesthetic sensation. According to an embodiment, the haptic module 179may include, for example, a motor, a piezoelectric element, or anelectric stimulator.

The camera module 180 may capture a still image and moving images.According to an embodiment, the camera module 180 may include one ormore lenses, image sensors, ISPs, or flashes.

The power management module 188 may manage power supplied to theelectronic device 101. According to an embodiment, the power managementmodule 188 may be implemented as at least part of, for example, a powermanagement integrated circuit (PMIC).

The battery 189 may supply power to at least one component of theelectronic device 101. According to an embodiment, the battery 189 mayinclude, for example, a primary cell which is not rechargeable, asecondary cell which is rechargeable, or a fuel cell.

The communication module 190 may support establishing a direct (e.g.,wired) communication channel or a wireless communication channel betweenthe electronic device 101 and the external electronic device (e.g., theelectronic device 102, the electronic device 104, or the server 108) andperforming communication via the established communication channel. Thecommunication module 190 may include one or more CPs that are operableindependently of the processor 120 (e.g., an AP) and that support adirect (e.g., wired) communication or a wireless communication.According to an embodiment, the communication module 190 may include awireless communication module 192 (e.g., a cellular communicationmodule, a short-range wireless communication module, or a globalnavigation satellite system (GNSS) communication module) or a wiredcommunication module 194 (e.g., a local area network (LAN) communicationmodule, or a power line communication (PLC) module). A corresponding oneof these communication modules may communicate with the externalelectronic device 104 via the first network 198 (e.g., a short-rangecommunication network, such as Bluetooth™, wireless-fidelity (Wi-Fi)direct, or infrared data association (IrDA)) or the second network 199(e.g., a long-range communication network, such as a legacy cellularnetwork, a fifth generation (5G) network, a next-generationcommunication network, the Internet, or a computer network (e.g., a LANor a wide area network (WAN))). These various types of communicationmodules may be implemented as a single component (e.g., a single chip),or may be implemented as multiple components (e.g., multiple chips)separate from each other. The wireless communication module 192 mayidentify and authenticate the electronic device 101 in a communicationnetwork, such as the first network 198 or the second network 199, usingsubscriber information (e.g., international mobile subscriber identity(IMSI)) stored in the SIM 196.

The wireless communication module 192 may support a 5G network after afourth generation (4G) network, and next-generation communicationtechnology, e.g., new radio (NR) access technology. The NR accesstechnology may support enhanced mobile broadband (eMBB), massive machinetype communications (mMTC), or ultra-reliable and low-latencycommunications (URLLC). The wireless communication module 192 maysupport a high-frequency band (e.g., a millimeter wave (mmWave) band) toachieve, e.g., a high data transmission rate. The wireless communicationmodule 192 may support various technologies for securing performance ona high-frequency band, such as, e.g., beamforming, massivemultiple-input and multiple-output (massive MIMO), full dimensional MIMO(FD-MIMO), an array antenna, analog beamforming, or a large scaleantenna. The wireless communication module 192 may support variousrequirements specified in the electronic device 101, an externalelectronic device (e.g., the electronic device 104), or a network system(e.g., the second network 199). According to an embodiment, the wirelesscommunication module 192 may support a peak data rate (e.g., 20 gigabitsper second (Gbps) or more) for implementing eMBB, loss coverage (e.g.,164 decibels (dB) or less) for implementing mMTC, or U-plane latency(e.g., 0.5 milliseconds (ms) or less for each of downlink (DL) anduplink (UL), or a round trip of 1 ms or less) for implementing URLLC.

The antenna module 197 may transmit or receive a signal or power to orfrom the outside (e.g., an external electronic device) of the electronicdevice 101. According to an embodiment, the antenna module 197 mayinclude an antenna including a radiating element including a conductivematerial or a conductive pattern formed in or on a substrate (e.g., aprinted circuit board (PCB)). According to an embodiment, the antennamodule 197 may include a plurality of antennas (e.g., array antennas).In such a case, at least one antenna appropriate for a communicationscheme used in a communication network, such as the first network 198 orthe second network 199, may be selected by, for example, thecommunication module 190 from the plurality of antennas. The signal orpower may be transmitted or received between the communication module190 and the external electronic device via the at least one selectedantenna. According to an embodiment, another component (e.g., a radiofrequency integrated circuit (RFIC)) other than the radiating elementmay be additionally formed as part of the antenna module 197.

According to various embodiments, the antenna module 197 may form ammWave antenna module. According to an embodiment, the mmWave antennamodule may include a PCB, an RFIC disposed on a first surface (e.g., thebottom surface) of the PCB or adjacent to the first surface and capableof supporting a designated high-frequency band (e.g., the mmWave band),and a plurality of antennas (e.g., array antennas) disposed on a secondsurface (e.g., the top or a side surface) of the PCB, or adjacent to thesecond surface and capable of transmitting or receiving signals in thedesignated high-frequency band.

At least some of the above-described components may be coupled mutuallyand communicate signals (e.g., commands or data) therebetween via aninter-peripheral communication scheme (e.g., a bus, general purposeinput and output (GPIO), serial peripheral interface (SPI), or mobileindustry processor interface (MIPI)).

According to an embodiment, commands or data may be transmitted orreceived between the electronic device 101 and the external electronicdevice 104 via the server 108 coupled with the second network 199. Eachof the external electronic devices 102 and 104 may be a device of thesame type as or a different type from the electronic device 101.According to an embodiment, all or some of operations to be executed atthe electronic device 101 may be executed at one or more of externalelectronic devices (e.g., the external electronic devices 102 and 104,or the server 108). For example, if the electronic device 101 needs toperform a function or a service automatically, or in response to arequest from a user or another device, the electronic device 101,instead of, or in addition to, executing the function or the service,may request the one or more external electronic devices to perform atleast part of the function or the service. The one or more externalelectronic devices receiving the request may perform the at least partof the function or the service requested, or an additional function oran additional service related to the request, and transfer an outcome ofthe performing to the electronic device 101. The electronic device 101may provide the outcome, with or without further processing of theoutcome, as at least part of a reply to the request. To that end, acloud computing, distributed computing, mobile edge computing (MEC), orclient-server computing technology may be used, for example. Theelectronic device 101 may provide ultra low-latency services using,e.g., distributed computing or MEC. In another embodiment, the externalelectronic device 104 may include an Internet-of-things (IoT) device.The server 108 may be an intelligent server using machine learningand/or a neural network. According to an embodiment, the externalelectronic device 104 or the server 108 may be included in the secondnetwork 199. The electronic device 101 may be applied to intelligentservices (e.g., a smart home, a smart city, a smart car, or healthcare)based on 5G communication technology or IoT-related technology.

An aluminum alloy extruded material according to various embodiments mayinclude aluminum (Al), zinc (Zn), magnesium (Mg), and copper (Cu).According to various embodiments, an oxide film may be formed on asurface of the aluminum alloy extruded material. An anodizing (anodicoxidation) operation may be performed on an aluminum alloy extrudedmaterial formed by adding zinc, magnesium, and copper to aluminum andmelting and extruding the mixture. As the anodizing operation isperformed, an oxide film may be formed on a surface of the aluminumalloy extruded material.

According to various embodiments, the oxide film may be formed on thesurface of the aluminum alloy extruded material, and a quality of anexterior of the aluminum alloy extruded material may be determinedaccording to a characteristic of the oxide film. In addition, the oxidefilm formed on the surface of the aluminum alloy extruded material maynot be easily detached.

According to various embodiments, an amount of copper and an amount ofzinc may correlate. According to various embodiments, the amount ofcopper and the amount of zinc in the aluminum alloy extruded materialmay satisfy Equation 1 below.

[Cu]≥0.14[Zn]−0.782  Equation 1

In Equation 1, [Cu] corresponds to an amount (% by weight (wt %)) ofcopper (Cu), and [Zn] corresponds to an amount (wt %) of zinc (Zn).

According to various embodiments, the minimum amount of copper may bedetermined according to the amount of zinc in the aluminum alloyextruded material. According to various embodiments, since zinc isincluded in the aluminum alloy extruded material, the aluminum alloyextruded material may be excellent in rigidity, and detachment of anoxide film formed by performing the anodizing operation may be preventedby adding copper together with zinc. According to various embodiments,when zinc is excessively included in the aluminum alloy extrudedmaterial beyond a predetermined range, the oxide film formed byperforming the anodizing operation may be easily detached, andaccordingly, copper may desirably be added together in a predeterminedrange. According to various embodiments, to prevent the oxide film frombeing detached, the amount of copper may be set in proportion to theamount of zinc in the aluminum alloy extruded material. According tovarious embodiments, the amount of copper and the amount of zin in thealuminum alloy extruded material may satisfy Equation 1 described above.Based on the total weight of the aluminum alloy extruded material, zincmay be included in an amount of 5.85 wt % to 8.0 wt % and copper may beincluded in an amount of 0.03 wt % to 0.50 wt %.

According to various embodiments, a cutting operation (e.g., computernumeric control (CNC) cutting) may be performed on the aluminum alloyextruded material to form an electronic device housing. When the cuttingoperation is performed, corrosion resistance and/or machinability of thealuminum alloy extruded material may desirably be high, to form adesired shape and/or form. According to various embodiments, thealuminum alloy extruded material that contains aluminum, zinc,magnesium, and copper and that is formed by extrusion may be processedin the form of a housing suitable for an electronic device as thecutting operation is performed. Since the aluminum alloy extrudedmaterial has a clean cut surface and is quickly cut due to excellentcorrosion resistance and/or machinability, the aluminum alloy extrudedmaterial may be desirably used to manufacture, in particular, asmall-sized part (e.g., a housing of a mobile electronic device).

According to various embodiments, the aluminum alloy extruded materialmay be cast through any manufacturing process performed according tostandards. As a series of manufacturing operations, for example, anoperation of melting aluminum and then adding other metal elements, anoperation of casting a billet for extrusion, a homogenizing heattreatment operation for a billet for extrusion, an operation ofperforming extrusion during heating at a high temperature, an artificialaging heat treatment operation for an aluminum alloy extruded through aheat treatment, a cutting step, and a surface oxidation treatmentoperation (anodizing step) may be included, however, the manufacturingoperations are not limited thereto. According to various embodiments,the artificial aging heat treatment operation may increase rigidity ofthe extruded aluminum alloy.

According to various embodiments, the aluminum alloy extruded materialmay be excellent in extrudability. For example, an operation ofextruding an aluminum alloy may be performed by applying heat at asolidus temperature or less of the aluminum alloy, and an extrusionspeed may be determined in consideration of a temperature rise due tofrictional heat during extrusion. The aluminum alloy extruded materialaccording to various embodiments may have a solidus temperature of 600°C. or higher and may be heated at a preheating temperature of 500° C. orhigher, so that an extrusion load during extrusion and flow stress maybe reduced.

According to various embodiments, the aluminum alloy extruded materialmay include metal elements including zinc, magnesium, and copper, andthe remainder may contain aluminum. According to various embodiments,zinc (Zn) may be included in an amount of 5.85 wt % to 8.0 wt % based onthe total weight of the aluminum alloy extruded material. Zinc may bebonded to magnesium in the aluminum alloy extruded material to form aZn₂Mg strengthening phase. When the amount of zinc is less than 5.85 wt%, yield strength may decrease, and when the amount of zinc exceeds 8 wt%, corrosion resistance may decrease, and a plurality of segregationsand a plurality of compounds containing zinc may be present in thealuminum alloy extruded material. For example, when the amount of zincis less than 5.85 wt % based on the total weight of the aluminum alloyextruded material, the yield strength may be less than 450 megapascals(MPa), and when the amount of zinc exceeds 8 wt %, gloss of a surface ofthe oxide film formed by performing the anodizing operation may bereduced to be less than 300 gloss units (GU), and surface roughening mayoccur.

According to various embodiments, magnesium (Mg) may be included in anamount of 2 wt % to 2.9 wt % based on the total weight of the aluminumalloy extruded material. When the amount of magnesium is less than 2 wt% based on the total weight of the aluminum alloy extruded material, theyield strength may decrease, and when the amount of magnesium exceeds2.9 wt %, extrudability may be reduced due to a low solidus temperatureof the aluminum alloy extruded material. For example, when the amount ofmagnesium is less than 2 wt % based on the total weight of the aluminumalloy extruded material, the yield strength may be less than 450 MPa,and when the amount of magnesium exceeds 2.9 wt %, it may be difficultto apply a high extrusion temperature, and accordingly, the extrusionspeed may decrease, a crack may occur, and gloss of the surface may bereduced to be less than 300 GU after the oxide film is formed throughthe anodizing step.

According to various embodiments, the amount of zinc and the amount ofmagnesium may satisfy Equation 2 below.

$\begin{matrix}{2 \leq \frac{\lbrack{Zn}\rbrack}{\lbrack{Mg}\rbrack} \leq 4} & {{Equation}2}\end{matrix}$

In Equation 2, [Zn] corresponds to the amount (wt %) of zinc (Zn), and[Mg] corresponds to the amount (wt %) of magnesium (Mg).

According to various embodiments, a ratio of the amount of zinc to theamount of magnesium in the aluminum alloy extruded material may rangefrom “2” to “4.” When the ratio of the amount of zinc to the amount ofmagnesium is less than “2,” the aluminum alloy extruded material mayhave high rigidity due to a relatively large amount of magnesium,however, at least one of the extrudability and/or extrusion speed may bereduced, and the surface gloss may be reduced after the anodizingoperation is performed. When the ratio of the amount of zinc to theamount of magnesium exceeds “4”, the corrosion resistance of thealuminum alloy extruded material may be reduced due to a relativelylarge amount of zinc, the surface gloss may be reduced after theanodizing operation is performed by at least one of a segregation and/orcompound formed by an excessive amount of zinc, and surface rougheningmay occur.

According to various embodiments, an intermetallic compound includingZn₂Mg may be formed by bonding zinc and magnesium in the aluminum alloyextruded material. The intermetallic compound may be formed by bondingbetween metal elements added to the aluminum alloy extruded material. Aplurality of intermetallic compounds may be dispersed in the aluminumalloy extruded material, and when the size of the intermetallic compounddecreases, a scratch may not be left on the oxide film on the surfacethat is etched as the anodizing operation is performed. As the number offine intermetallic compounds with a small diameter increases, the glossmay increase. According to various embodiments, the diameter of theintermetallic compound may be 10 micrometers (μm) or less. Desirably,the diameter of the intermetallic compound may be 6 μm or less. Forexample, the diameter of the intermetallic compound may refer to anaverage diameter of intermetallic compounds.

According to various embodiments, the aluminum alloy extruded materialmay be formed of a plurality of grain structures. The aluminum alloyextruded material may be formed by extruding an aluminum alloy formed bycasting dissolved aluminum, and crystal grains may be formed during acooling process in which the aluminum alloy extruded material isgradually cooled. The size of a crystal grain of the aluminum alloyextruded material may be determined according to at least one of thetype and/or operation conditions of post-casting operations. Forexample, when a speed at which the aluminum alloy after casting iscooled increases, the size of a crystal grain in the aluminum alloy maydecrease.

According to various embodiments, crystal grains of the aluminum alloyextruded material may have an average particle diameter of 100 μm to 300μm, desirably, 150 μm to 300 μm. At least two crystal grains may beadjacent to each other at an edge and may form a grain boundary at theedge, and at least two adjacent crystal grains based on the grainboundary may have different potentials. According to variousembodiments, a potential difference at an interface between at least twoadjacent crystal grains in the aluminum alloy extruded material mayrange from 30 millivolts (mV) to 100 mV, and desirably, a potentialdifference between at least two crystal grains at a grain boundary mayrange from 30 mV to 50 mV.

According to various embodiments, the aluminum alloy extruded materialmay include copper (Cu). According to various embodiments, the coppermay be included in an amount of 0.03 wt % to 0.50 wt % based on thetotal weight of the aluminum alloy extruded material. According tovarious embodiments, when the amount of copper is less than 0.03 wt %based on the total weight of the aluminum alloy extruded material, thecorrosion resistance may decrease due to an increase in a potentialdifference at a grain boundary in the aluminum alloy extruded material,and durability of the oxide film formed by performing the anodizingoperation may decrease. In addition, when the amount of copper exceeds0.50 wt % based on the total weight of the aluminum alloy extrudedmaterial, the overall corrosion resistance of the aluminum alloyextruded material may be greatly reduced, and a color tone of the oxidefilm formed by performing the anodizing operation may change to yellow,which may lead to a reduction in the exterior quality. For example, whencopper is included in an amount of 0.03 wt % to 0.50 wt % based on thetotal weight of the aluminum alloy extruded material, a cut surface maybe smoothly formed in a cutting operation (e.g., a CNC cutting step) dueto excellent corrosion resistance, a color tone of a surface may notchange to yellow even though the oxide film is formed through theanodizing step, and the yield strength may be increased by 5 MPa to 10MPa due to the enhanced rigidity.

According to various embodiments, the aluminum alloy extruded materialmay include manganese (Mn), and manganese may be included in an amountof 0.1 wt % to 0.3 wt % based on the total weight of the aluminum alloyextruded material. According to various embodiments, when the amount ofmanganese is greater than or equal to 0.1 wt % based on the total weightof the aluminum alloy extruded material, the surface gloss and glossuniformity may be enhanced during the anodizing operation by uniformlycontrolling the average particle diameter of crystal grains in thealuminum alloy extruded material. In addition, the rigidity may beenhanced due to a solid-solution strengthening effect caused bypermeation of manganese into the aluminum alloy extruded material, and areduction in the corrosion resistance due to the remaining excessiveiron by forming a compound with iron may be mitigated. When the amountof manganese exceeds 0.3 wt % based on the total weight of the aluminumalloy extruded material, the surface gloss may be reduced as excessivemanganese is dispersed.

According to various embodiments, the aluminum alloy extruded materialmay include silicon (Si), and silicon may be included in an amount of0.01 wt % to 0.1 wt % based on the total weight of the aluminum alloyextruded material. According to various embodiments, when the amount ofsilicon is greater than or equal to 0.01 wt % based on the total weightof the aluminum alloy extruded material, silicon may react withexcessive iron to mitigate a reduction in the corrosion resistance dueto the remaining excessive iron. In addition, when the amount of siliconexceeds 0.1 wt % based on the total weight of the aluminum alloyextruded material, an average particle diameter of intermetalliccompounds formed by a reaction with iron may exceed 10 μm, and thesurface gloss may be greatly reduced by the intermetallic compoundsdispersed on the surface.

According to various embodiments, the aluminum alloy extruded materialmay include iron (Fe), and the iron may be included in an amount of 0.01wt % to 0.15 wt % based on the total weight of the aluminum alloyextruded material. According to various embodiments, when the amount ofiron is greater than or equal to 0.01 wt % based on the total weight ofthe aluminum alloy extruded material, at least one of adhesion, seizureresistance, and/or frictional force to a mold during an extrusionoperation may be reduced. When the amount of iron exceeds 0.15 wt %, thesurface gloss may be reduced by forming an intermetallic compound with aparticle diameter of 10 μm or greater together with silicon ormanganese, and machinability may be reduced during a cutting operation(e.g., a CNC cutting step), so that a cut surface may not be smooth.According to various embodiments, the iron may be desirably included inan amount of 0.07 wt % or less based on the total weight of the aluminumalloy extruded material.

According to various embodiments, the aluminum alloy extruded materialmay include titanium (Ti), and the titanium may be included in an amountof 0.005 wt % to 0.03 wt % based on the total weight of the aluminumalloy extruded material. According to various embodiments, when theamount of titanium is greater than or equal to 0.005 wt % based on thetotal weight of the aluminum alloy extruded material, crystal grains inthe aluminum alloy extruded material may be uniformly formed to have anaverage diameter of 300 μm or less, the surface gloss and/or glossuniformity of the oxide film according to the anodizing operation may beincreased, and a crack may not occur during extrusion. According tovarious embodiments, when the amount of titanium exceeds 0.03 wt % basedon the total weight of the aluminum alloy extruded material, a compoundformed by excessive titanium may have various shapes (e.g., a linearshape) on the surface of the aluminum alloy extruded material.

According to various embodiments, the aluminum alloy extruded materialmay include zirconium (Zr), and the zirconium may be included in anamount of 0.005 wt % to 0.03 wt % based on the total weight of thealuminum alloy extruded material. According to various embodiments, whenthe amount of zirconium is greater than or equal to 0.005 wt % based onthe total weight of the aluminum alloy extruded material, crystal grainsin the aluminum alloy extruded material may be uniformly formed to havean average diameter of 300 μm or less, the surface gloss and/or glossuniformity of the oxide film according to the anodizing operation may beincreased, and a crack may not occur during extrusion. According tovarious embodiments, when the amount of zirconium exceeds 0.03 wt %based on the total weight of the aluminum alloy extruded material, acompound formed by excessive zirconium may have various shapes (e.g., alinear shape) on the surface of the aluminum alloy extruded material.

According to various embodiments, the aluminum alloy extruded materialmay include chromium (Cr), and the chromium may be included in an amountof 0.0001 wt % to 0.03 wt % based on the total weight of the aluminumalloy extruded material. According to various embodiments, when theamount of chromium is greater than or equal to 0.0001 wt % based on thetotal weight of the aluminum alloy extruded material, the averagediameter of the crystal grains may be maintained at 10 μm or less, therigidity may increase, and internal stress corrosion cracking in thealuminum alloy extruded material may be mitigated. When the amount ofchromium exceeds 0.03 wt %, the color tone of the surface may change(e.g., change to yellow) as the anodizing operation is performed,thereby reducing the exterior quality.

According to various embodiments, the aluminum alloy extruded materialmay include copper (Cu) and zinc (Zn), and the amount of copper and theamount of zinc may satisfy Equation 3 below.

$\begin{matrix}{0.003 \leq \frac{\lbrack{Cu}\rbrack}{\lbrack{Zn}\rbrack} \leq 0.375} & {{Equation}3}\end{matrix}$

In Equation 3, [Cu] corresponds to an amount (wt %) of copper (Cu), and[Zn] corresponds to an amount (wt %) of zinc (Zn).

According to various embodiments, a ratio of the amount of copper to theamount of zinc in the aluminum alloy extruded material may range from“0.003” to “0.375.” When the ratio of the amount of copper to the amountof zinc is less than “0.003,” the oxide film formed through theanodizing operation may be easily detached due to a relatively largeamount of zinc, and when the ratio of the amount of copper to the amountof zinc exceeds “0.375,” the corrosion resistance may be greatly reduceddue to a relatively large amount of copper, and the color tone maychange (e.g., a yellowing phenomenon occurs) as the anodizing operationis performed.

According to various embodiments, the aluminum alloy extruded materialmay include copper (Cu) and zinc (Zn), and the amount of copper and theamount of zinc may satisfy Equation 4 below.

$\begin{matrix}{\frac{\lbrack{Cu}\rbrack}{\lbrack{Zn}\rbrack} \geq {0.14 - \frac{0.782}{\lbrack{Zn}\rbrack}}} & {{Equation}4}\end{matrix}$

In Equation 4, [Cu] corresponds to an amount (wt %) of copper (Cu), and[Zn] corresponds to an amount (wt %) of zinc (Zn).

According to various embodiments, in the aluminum alloy extrudedmaterial, the ratio of the amount of copper to the amount of zinc may bedetermined according to the amount of zinc. According to variousembodiments, when zinc is excessively included in the aluminum alloyextruded material beyond a predetermined range, the oxide film formed byperforming the anodizing operation may be easily detached, andaccordingly, copper may desirably be added together in a predeterminedrange. According to various embodiments, to prevent the oxide film frombeing detached, the ratio of the amount of copper to the amount of zincmay be set according to the amount of zinc in the aluminum alloyextruded material. According to various embodiments, the amount ofcopper and the amount of zinc in the aluminum alloy extruded materialmay satisfy Equation 4 described above. Based on the total weight of thealuminum alloy extruded material, zinc may be included in an amount of5.85 wt % to 8.0 wt % and copper may be included in an amount of 0.03 wt% to 0.50 wt %.

According to various embodiments, the aluminum alloy extruded materialmay have a yield strength of 450 MPa or greater. According to variousembodiments, a homogenization operation through a heat treatment may beperformed on the aluminum alloy extruded material, and the yieldstrength of the aluminum alloy extruded material may be 460 MPa orgreater, 465 MPa or greater, 470 MPa or greater, 480 MPa or greater, 490MPa or greater, 500 MPa or greater, 510 MPa or greater, 520 MPa orgreater, 530 MPa or greater, or 540 MPa or greater.

According to various embodiments, the aluminum alloy extruded materialmay have a surface hardness of 150 Vickers hardness (Hv) or greater. Thesurface hardness may be measured according to a Vickers hardnessmeasurement method. Specifically, the hardness may be measured bypressing an aluminum alloy extruded material using a pyramid-shapeddiamond indenter in the form of a quadrangular pyramid having a faceangle of 136° and by using a diagonal length of a concave portion of apyramid shape formed by pressing the aluminum alloy extruded material.According to various embodiments, the surface hardness of the aluminumalloy extruded material may be 160 Hv or greater, 170 Hv or greater, 180Hv or greater, 190 Hv or greater, 200 Hv or greater, or 210 Hv orgreater.

An electronic device housing according to various embodiments mayinclude an aluminum alloy extruded material according to an embodiment.For example, the aluminum alloy extruded material may be used as ahousing of an electronic device including at least one of a mobile phoneand/or a tablet computer. According to various embodiments, the aluminumalloy extruded material may be used to prepare a housing for an outercasing of a mobile phone (e.g., a smartphone) and tablet bottom chassis.

According to various embodiments, the aluminum alloy extruded materialmay have a surface gloss of 300 GU or greater measured according toInternational Organization for Standardization (ISO) 2813. According toan embodiment, the aluminum alloy extruded material may be used for ahousing (e.g., an exterior frame of the electronic device) of theelectronic device to protect internal components and modules of theelectronic device. According to an embodiment, the aluminum alloyextruded material may be glossy so that the exterior of the electronicdevice may be made aesthetic.

According to various embodiments, the surface gloss of the aluminumalloy extruded material may be measured according to ISO 2813, thestandard of the International Organization for Standardization.According to ISO 2813, surface gloss of an uncolored specimen with athickness of about 10 μm is measured, and an amount of light to beincident at 60° and reflected is measured to measure the surface glossof the surface of the aluminum alloy extruded material.

According to various embodiments, the aluminum alloy extruded materialmay include aluminum (Al), zinc (Zn), and magnesium (Mg), and may havethe surface gloss of 300 GU or greater measured according to ISO 2813.

According to various embodiments, the amount of zinc and the amount ofmagnesium may satisfy Equation 2 below.

$\begin{matrix}{2 \leq \frac{\lbrack{Zn}\rbrack}{\lbrack{Mg}\rbrack} \leq 4} & {{Equation}2}\end{matrix}$

In Equation 2, [Zn] corresponds to the amount (wt %) of zinc (Zn), and[Mg] corresponds to the amount (wt %) of magnesium (Mg).

According to various embodiments, the aluminum alloy extruded materialmay further include an intermetallic compound including Zn₂Mg, and theintermetallic compound may have a diameter of 10 μm or less.

According to various embodiments, the aluminum alloy extruded materialmay include crystal grains having the average particle diameter of 100μm to 300 μm, and a potential difference at an interface between atleast two adjacent crystal grains may be in the range of 30 mV to 100mV.

According to various embodiments, zinc may be present in an amount of5.85 wt % to 8.0 wt %, and magnesium may be present in an amount of 2.0wt % to 2.9 wt %.

According to various embodiments, the aluminum alloy extruded materialmay further include copper (Cu), and the copper may be included in anamount of 0.03 wt % to 0.50 wt %.

According to various embodiments, the aluminum alloy extruded materialmay further include copper (Cu), and the amount of copper and the amountof zinc may satisfy Equation 3 below.

$\begin{matrix}{0.003 \leq \frac{\lbrack{Cu}\rbrack}{\lbrack{Zn}\rbrack} \leq 0.375} & {{Equation}3}\end{matrix}$

In Equation 3, [Cu] corresponds to an amount (wt %) of copper (Cu), and[Zn] corresponds to an amount (wt %) of zinc (Zn).

According to various embodiments, the aluminum alloy extruded materialmay further include copper (Cu), and the amount of copper and the amountof zinc may satisfy Equation 4 below.

$\begin{matrix}{\frac{\lbrack{Cu}\rbrack}{\lbrack{Zn}\rbrack} \geq {0.14 - \frac{0.782}{\lbrack{Zn}\rbrack}}} & {{Equation}4}\end{matrix}$

In Equation 4, [Cu] corresponds to an amount (wt %) of copper (Cu), and[Zn] corresponds to an amount (wt %) of zinc (Zn).

According to various embodiments, the aluminum alloy extruded materialmay further include manganese (Mn), silicon (Si), iron (Fe), titanium(Ti), zirconium (Zr), and chromium (Cr), manganese may be present in anamount of 0.1 wt % to 0.3 wt %, silicon may be present in an amount of0.01 wt % to 0.1 wt %, iron may be present in an amount of 0.01 wt % to0.15 wt %, titanium may be present in an amount of 0.005 wt % to 0.03 wt%, zirconium may be present in an amount of 0.005 wt % to 0.03 wt %, andchromium may be present in an amount of 0.0001 wt % to 0.03 wt %.

According to various embodiments, the aluminum alloy extruded materialmay further include copper (Cu), manganese (Mn), silicon (Si), iron(Fe), titanium (Ti), zirconium (Zr), and chromium (Cr). Zinc may bepresent in an amount of 5.85 wt % to 8.0 wt, magnesium may be present inan amount of 2.0 wt % to 2.9 wt %, copper may be present in an amount of0.03 wt % to 0.50 wt %, manganese may be present in an amount of 0.1 wt% to 0.3 wt %, silicon may be present in an amount of 0.01 wt % to 0.1wt, iron may be present in an amount of 0.01 wt % to 0.15 wt %, titaniummay be present in an amount of 0.005 wt % to 0.03 wt %, zirconium may bepresent in an amount of 0.005 wt % to 0.03 wt %, chromium may be presentin an amount of 0.0001 wt % to 0.03 wt %, and aluminum may account forthe remainder.

According to various embodiments, the aluminum alloy extruded materialmay have a yield strength of 450 MPa or greater.

According to various embodiments, the aluminum alloy extruded materialmay have a surface hardness of 150 Hv or greater.

According to various embodiments, the aluminum alloy extruded materialmay have the surface gloss of 300 GU or greater measured according toISO 2813.

According to various embodiments, the electronic device housing mayinclude an aluminum alloy extruded material according to variousembodiments.

FIG. 2 is a flowchart of operations of a method of preparing an aluminumalloy extruded material according to an embodiment of the disclosure.

Referring to FIG. 2 , the method of preparing the aluminum alloyextruded material may include operation 210 of preparing an aluminummetal, operation 220 of forming an aluminum alloy by melting thealuminum metal and adding metal elements using zinc and magnesium,operation 230 of heating and extruding the aluminum alloy, and operation240 of performing a heat treatment on the aluminum alloy.

According to various embodiments, to form an aluminum alloy, aluminum ora master alloy may be prepared and melted. For example, metal elementsincluding zinc and magnesium may be added to a molten metal obtained bymelting the aluminum alloy by heating pure aluminum (AI) at atemperature of 850° C. or higher, to form an alloy. The metal elementsmay be simultaneously or sequentially added, and may be added by addinga metal flux containing a large amount of metal elements to moltenaluminum.

According to various embodiments, the metal elements added in operation220 of forming the aluminum alloy may further include at least one ofcopper (Cu), manganese (Mn), silicon (Si), iron (Fe), titanium (Ti),zirconium (Zr) and/or chromium (Cr). According to various embodiments, acharacteristic of the aluminum alloy extruded material obtained after anextrusion operation may be determined according to the amount of metalelements added in operation 220 of forming the aluminum alloy.

According to various embodiments, zinc (Zn) may be included in an amountof 5.85 wt % to 8.0 wt % based on the total weight of the aluminumalloy. Zinc may be bonded to magnesium in the aluminum alloy to form aZn₂Mg strengthening phase. When the amount of zinc is less than 5.85 wt%, yield strength of the aluminum alloy formed by extrusion maydecrease, and when the amount of zinc exceeds 8 wt %, corrosionresistance may decrease, and a plurality of segregations and a pluralityof compounds containing zinc may be present in the aluminum alloyextruded material. For example, when the amount of zinc is less than5.85 wt % based on the total weight of the aluminum alloy, the yieldstrength of the aluminum alloy extruded material may be less than 450MPa, and when the amount of zinc exceeds 8 wt %, gloss of a surface ofan oxide film formed by performing an anodizing operation may be reducedto be less than 300 GU, and surface roughening may occur.

According to various embodiments, magnesium (Mg) may be included in anamount of 2 wt % to 2.9 wt % based on the total weight of the aluminumalloy. When the amount of magnesium is less than 2 wt % based on thetotal weight of the aluminum alloy, the yield strength of the aluminumalloy extruded material formed by extrusion may decrease, and when theamount of magnesium exceeds 2.9 wt %, extrudability may be reduced dueto a low solidus temperature of the aluminum alloy extruded material.For example, when the amount of magnesium is less than 2 wt % based onthe total weight of the aluminum alloy, the yield strength may be lessthan 450 MPa, and when the amount of magnesium exceeds 2.9 wt %, it maybe difficult to apply a high extrusion temperature, and accordingly anextrusion speed may decrease, a crack may occur, and gloss of a surfacemay be reduced to be less than 300 GU after the oxide film is formedthrough the anodizing operation.

According to various embodiments, copper (Cu) may be included in anamount of 0.03 wt % to 0.50 wt % based on the total weight of thealuminum alloy. According to various embodiments, when the amount ofcopper is less than 0.03 wt % based on the total weight of the aluminumalloy, the corrosion resistance may decrease due to an increase in apotential difference at a grain boundary in the aluminum alloy extrudedmaterial, and durability of the oxide film formed by performing theanodizing operation may decrease. In addition, when the amount of copperexceeds 0.50 wt % based on the total weight of the aluminum alloy, theoverall corrosion resistance of the aluminum alloy extruded material maybe greatly reduced, and a color tone of the oxide film formed byperforming the anodizing operation may change to yellow, which may leadto a reduction in the exterior quality. For example, when copper isincluded in an amount of 0.03 wt % to 0.50 wt % based on the totalweight of the aluminum alloy, a cut surface may be smoothly formed in acutting operation (e.g., a CNC cutting operation) due to excellentcorrosion resistance, a color tone of a surface may not change to yelloweven though the oxide film is formed through the anodizing operation,and the yield strength may be increased by 5 MPa to 10 MPa due to theenhanced rigidity.

According to various embodiments, manganese (Mn) may be included in anamount of 0.1 wt % to 0.3 wt % based on the total weight of the aluminumalloy. According to various embodiments, when the amount of manganese isgreater than or equal to 0.1 wt % based on the total weight of thealuminum alloy, the surface gloss and gloss uniformity may be enhancedduring the anodizing operation by uniformly controlling the averageparticle diameter of crystal grains in the aluminum alloy. In addition,the rigidity may be enhanced due to a solid-solution strengtheningeffect caused by permeation of manganese into the aluminum alloyextruded material, and a reduction in the corrosion resistance due tothe remaining excessive iron by forming a compound with iron may bemitigated. When the amount of manganese exceeds 0.3 wt % based on thetotal weight of the aluminum alloy, the surface gloss may be reduced asexcessive manganese is dispersed.

According to various embodiments, silicon (Si) may be included in anamount of 0.01 wt % to 0.1 wt % based on the total weight of thealuminum alloy. According to various embodiments, when the amount ofsilicon is greater than or equal to 0.01 wt % based on the total weightof the aluminum alloy, silicon may react with excessive iron to mitigatea reduction in the corrosion resistance due to the remaining excessiveiron. In addition, when the amount of silicon exceeds 0.1 wt % based onthe total weight of the aluminum alloy, an average particle diameter ofintermetallic compounds formed by a reaction with iron may exceed 10 μm,and the surface gloss may be greatly reduced by the intermetalliccompounds dispersed on the surface.

According to various embodiments, iron (Fe) may be included in an amountof 0.01 wt % to 0.15 wt % based on the total weight of the aluminumalloy. According to various embodiments, when the amount of iron isgreater than or equal to 0.01 wt % based on the total weight of thealuminum alloy, at least one of adhesion, seizure resistance, and/orfrictional force to a mold during an extrusion operation may be reduced.When the amount of iron exceeds 0.15 wt %, the surface gloss may bereduced by forming an intermetallic compound with a particle diameter of10 μm or greater together with silicon or manganese, and machinabilitymay be reduced during a cutting operation (e.g., a CNC cuttingoperation), so that a cut surface may not be smooth. According tovarious embodiments, iron may desirably be included in an amount of 0.07wt % or less based on the total weight of the aluminum alloy.

According to various embodiments, titanium (Ti) may be included in anamount of 0.005 wt % to 0.03 wt % based on the total weight of thealuminum alloy. According to various embodiments, when the amount oftitanium is greater than or equal to 0.005 wt % based on the totalweight of the aluminum alloy, crystal grains in the aluminum alloyextruded material may be uniformly formed to have an average diameter of300 μm or less, the surface gloss and/or gloss uniformity of the oxidefilm according to the anodizing operation may be increased, and a crackmay not occur during extrusion. According to various embodiments, whenthe amount of titanium exceeds 0.03 wt % based on the total weight ofthe aluminum alloy, a compound formed by excessive titanium may havevarious shapes (e.g., a linear shape) on the surface of the aluminumalloy extruded material.

According to various embodiments, zirconium (Zr) may be included in anamount of 0.005 wt % to 0.03 wt % based on the total weight of thealuminum alloy. According to various embodiments, when the amount ofzirconium is greater than or equal to 0.005 wt % based on the totalweight of the aluminum alloy, crystal grains in the aluminum alloyextruded material may be uniformly formed to have an average diameter of300 μm or less, the surface gloss and/or gloss uniformity of the oxidefilm according to the anodizing operation may be increased, and a crackmay not occur during extrusion. According to various embodiments, whenthe amount of zirconium exceeds 0.03 wt % based on the total weight ofthe aluminum alloy, a compound formed by excessive zirconium may havevarious shapes (e.g., a linear shape) on the surface of the aluminumalloy extruded material.

According to various embodiments, chromium (Cr) may be included in anamount of 0.0001 wt % to 0.03 wt % based on the total weight of thealuminum alloy. According to various embodiments, when the amount ofchromium is greater than or equal to 0.0001 wt % based on the totalweight of the aluminum alloy extruded material, the average diameter ofthe crystal grains may be maintained at 10 μm or less, the rigidity mayincrease, and internal stress corrosion cracking in the aluminum alloyextruded material may be mitigated. When the amount of chromium exceeds0.03 wt %, the color tone of the surface may change (e.g., change toyellow) as the anodizing operation is performed, thereby reducing theexterior quality.

According to various embodiments, in operation 220 of forming thealuminum alloy, a billet for extrusion may be formed, and a diameter ofthe billet may range from 4 inches to 10 inches.

According to various embodiments, after operation 220 of forming thealuminum alloy, an operation of performing a homogenizing heat treatmenton the aluminum alloy may be further performed. According to variousembodiments, the operation of performing the homogenizing heat treatmentmay be performed for homogenization by equilibrating a concentrationgradient of metal elements in the extruded aluminum alloy and may beperformed to make nonuniform microstructures uniform as a whole. In theoperation of performing the homogenizing heat treatment, heating may beperformed at a high temperature (e.g., 450° C. to 650° C., desirably500° C. to 650° C., below the solvus temperature of the aluminum alloy)for several hours or less, for example, a period of 30 hours or less.

According to various embodiments, operation 230 of extruding thealuminum alloy may be performed simultaneously with heating. Accordingto various embodiments, operation 230 of extruding the aluminum alloymay be performed by inserting the aluminum alloy into an extruder, andmay be performed simultaneously with heating to reduce extrusion stress.According to various embodiments, the temperature of the aluminum alloymay further rise due to extrusion friction in the extruder duringextruding. The extrusion speed of the alloy and/or a temperature atwhich the aluminum alloy is inserted into the extruder may becontrolled, to control heating so that the aluminum alloy may beprevented from being heated up to solidus temperature or greater duringextrusion of the aluminum alloy. According to various embodiments, across-sectional area of the aluminum alloy may be reduced by 90% orgreater through operation 230 of extruding the aluminum alloy.

According to various embodiments, operation 240 of performing the heattreatment on the extruded aluminum alloy may be performed at atemperature of 210° C. or less. According to various embodiments,operation 240 of performing the heat treatment may be performed at atemperature of 200° C. or less, 190° C. or less, 180° C. or less, or170° C. or less. According to various embodiments, the aluminum alloyextruded through operation 240 of performing the heat treatment may beformed as an aluminum alloy extruded material, and operation 240 ofperforming the heat treatment may be performed for 1 hour to 48 hours.According to various embodiments, as an intermetallic compound (e.g.,Zn₂Mg) is precipitated through operation 240 of performing the heattreatment, the rigidity of the aluminum alloy extruded material may begreatly enhanced.

FIG. 3 is a flowchart of a method of preparing an aluminum alloyextruded material according to an embodiment of the disclosure.

Referring to FIG. 3 , the method of preparing the aluminum alloyextruded material may include operation 310 (e.g., operation 210 of FIG.2 ) of preparing an aluminum metal, operation 320 (e.g., operation 220of FIG. 2 ) of forming an aluminum alloy by melting the aluminum metaland adding metal elements using zinc and magnesium, operation 330 (e.g.,operation 230 of FIG. 2 ) of heating and extruding the aluminum alloy,operation 340 (e.g., operation 240 of FIG. 2 ) of performing a heattreatment on the aluminum alloy, and operation 350 of anodizing analuminum alloy extruded material formed through the above operations.

According to various embodiments, operation 350 of anodizing thealuminum alloy extruded material may be performed to form an oxide filmon a surface of the aluminum alloy extruded material. Prior to operation350 of anodizing the aluminum alloy extruded material, a cuttingoperation (not shown) for the aluminum alloy extruded material to have aspecific shape and form may be further included. The cutting operationmay be performed, for example, through CNC cutting. For example, throughthe cutting operation, the aluminum alloy extruded material may have ashape and/or form to be used as a housing of an electronic device (e.g.,a mobile electronic device, a laptop, a portable terminal, etc.).

According to various embodiments, an oxide film may be formed on thesurface of the aluminum alloy extruded material through operation 350 ofanodizing the aluminum alloy extruded material so that the surface maybe treated. Operation 350 of anodizing the aluminum alloy extrudedmaterial may be performed by immersing the aluminum alloy extrudedmaterial in a solution containing at least one of sulfuric acid, nitricacid, phosphoric acid, oxalic acid, and chromic acid under a currentdensity of 0.5 A/dm³ to 2 A/dm³.

Hereinafter, the disclosure will be described in more detail withreference to examples and comparative examples.

However, the following examples are only for illustrating thedisclosure, and the disclosure is not limited to the following examples.

EXAMPLES AND COMPARATIVE EXAMPLES

Aluminum alloy extruded materials may be prepared by adding variousmetal elements to pure aluminum. Compositions of aluminum alloys ofexamples and comparative examples may be shown in Table 1 below byadding different amounts of metal elements based on the total weight ofthe aluminum alloy extruded material.

TABLE 1 Zn Mg Cu Mn Si Fe Ti Zr Cr Al Item [wt %] [wt %] [wt %] [wt %][wt %] [wt %] [wt %] [wt %] [wt %] [wt %] Example 1 5.85 2.0 0.03 0.10.01 0.01 0.005 0.005 0.0001 Remainder Example 2 5.85 2.9 0.03 0.1 0.010.01 0.005 0.005 0.0001 Remainder Example 3 5.85 2.9 0.50 0.3 0.1 0.150.03 0.03 0.03 Remainder Example 4 6.1 2.0 0.06 0.1 0.01 0.01 0.0050.005 0.0001 Remainder Example 5 6.1 2.1 0.03 0.15 0.06 0.07 0.015 0.0150.015 Remainder Example 6 6.1 2.9 0.50 0.3 0.1 0.15 0.03 0.03 0.03Remainder Example 7 6.3 2.3 0.03 0.15 0.06 0.07 0.015 0.015 0.015Remainder Example 8 7.0 2.0 0.03 0.1 0.01 0.01 0.005 0.005 0.0001Remainder Example 9 7.0 2.9 0.50 0.3 0.1 0.15 0.03 0.03 0.03 RemainderExample 10 8.0 2.0 0.03 0.1 0.01 0.01 0.005 0.005 0.0001 RemainderExample 11 8.0 2.9 0.50 0.3 0.1 0.15 0.03 0.03 0.03 RemainderComparative 5.8 2.0 0.03 0.1 0.01 0.01 0.005 0.005 0.0001 RemainderExample 1 Comparative 8.2 2.0 0.03 0.1 0.01 0.01 0.005 0.005 0.0001Remainder Example 2 Comparative 8.3 2.9 0.50 0.3 0.1 0.15 0.03 0.03 0.03Remainder Example 3

Heat treatments may be performed on aluminum alloys of Examples 1 to 11and Comparative Examples 1 to 3 according to Table 1 at 210° C., tohomogenize each of the aluminum alloys. An electronic device housinghaving an oxide film formed on a surface thereof may be manufactured asan electronic device housing through a CNC cutting operation and ananodizing operation of aluminum alloy extruded materials formedaccording to the examples and comparative examples.

Experimental Example

For the aluminum alloy extruded materials according to Examples 1 to 11and Comparative Examples 1 to 3, yield strength, Vickers surfacehardness, and gloss of a surface of an oxide film may be measured. Theyield strength, surface hardness and surface gloss of the aluminum alloyextruded materials may be measured according to KS D 8301, and theresults may be shown in Table 2 below.

TABLE 2 Yield Surface Item strength [MPa] Hardness [Hv] gloss [GU]Example 1 451 160 408 Example 2 504 189 400 Example 3 517 195 390Example 4 460 169 381 Example 5 465 172 381 Example 6 531 205 365Example 7 498 179 348 Example 8 507 187 330 Example 9 533 210 346Example 10 519 202 318 Example 11 549 215 325 Comparative 448 157 408Example 1 Comparative 519 204 280 Example 2 Comparative 588 220 220Example 3

In addition, a cross section of an aluminum alloy extruded materialaccording to an embodiment may be observed with a microscope, as shownin FIG. 4 .

FIG. 4 is an image obtained by capturing a cross section of an aluminumalloy extruded material according to an embodiment of the disclosure.

Referring to FIG. 4 , the aluminum alloy extruded material may include aplurality of grain structures. Crystal grains may have the same size ordifferent sizes, and have an average particle diameter of 100 μm to 300μm. In addition, an intermetallic compound may be formed within crystalgrains or at a grain boundary. An intermetallic compound (e.g., Zn₂Mg)may be formed by binding of excessive metal elements (e.g., magnesium,zinc, iron, silicon, manganese, etc.) other than aluminum. In addition,the intermetallic compound may be in the form of small black grains, forexample, needles. The average particle diameter of intermetalliccompounds may be 100 μm to 300 μm, desirably 150 μm to 300 μm. Inaddition, one crystal grain and another adjacent crystal grain may forma grain boundary that is an adjacent boundary, and at least two adjacentcrystal grains based on the grain boundary may have differentpotentials.

Whether oxide films formed on surfaces of the aluminum alloy extrudedmaterials according to Example 1 and Comparative Example 1 are detachedmay be tested. Adhesion of an oxide film may be observed based onwhether the oxide film is detached after the oxide film is scratchedwith a knife blade and attached and detached several times using a tapeaccording to ISO 2409 or American Society for Testing and Materials(ASTM) D3359-17.

The electronic device according to various embodiments disclosed hereinmay be one of various types of electronic devices. The electronicdevices may include, for example, a portable communication device (e.g.,a smartphone), a computer device, a portable multimedia device, aportable medical device, a camera, a wearable device, or a homeappliance. According to an embodiment of the disclosure, the electronicdevice is not limited to those described above.

It should be appreciated that various embodiments of the disclosure andthe terms used therein are not intended to limit the technologicalfeatures set forth herein to particular embodiments and include variouschanges, equivalents, or replacements for a corresponding embodiment.With regard to the description of the drawings, similar referencenumerals may be used to refer to similar or related elements. As usedherein, each of such phrases as “A or B,” “at least one of A and B,” “atleast one of A or B,” “A, B or C,” “at least one of A, B and C,” and “atleast one of A, B, or C,” may include any one of, or all possiblecombinations of the items enumerated together in a corresponding one ofthe phrases. As used herein, such terms as “1^(st)” and “2^(nd),” or“first” and “second” may be used to simply distinguish a correspondingcomponent from another, and does not limit the components in otheraspect (e.g., importance or order). It is to be understood that if acomponent (e.g., a first component) is referred to, with or without theterm “operatively” or “communicatively,” as “coupled with,” “coupledto,” “connected with,” or “connected to” another component (e.g., asecond component), it denotes that the component may be coupled with theother component directly (e.g., by wire), wirelessly, or via a thirdcomponent.

As used in connection with various embodiments of the disclosure, theterm “module” may include a unit implemented in hardware, software, orfirmware, and may interchangeably be used with other terms, for example,“logic,” “logic block,” “part,” or “circuitry.” A module may be a singleintegral component, or a minimum unit or part thereof, adapted toperform one or more functions. For example, according to an embodiment,the module may be implemented in a form of an application-specificintegrated circuit (ASIC).

Various embodiments as set forth herein may be implemented as software(e.g., the program 140) including one or more instructions that arestored in a storage medium (e.g., an internal memory 136 or an externalmemory 138) that is readable by a machine (e.g., the electronic device101). For example, a processor (e.g., the processor 120) of the machine(e.g., the electronic device 101) may invoke at least one of the one ormore instructions stored in the storage medium, and execute it. Thisallows the machine to be operated to perform at least one functionaccording to the at least one instruction invoked. The one or moreinstructions may include code generated by a compiler or code executableby an interpreter. The machine-readable storage medium may be providedin the form of a non-transitory storage medium. Here, the term“non-transitory” simply denotes that the storage medium is a tangibledevice, and does not include a signal (e.g., an electromagnetic wave),but this term does not differentiate between where data issemi-permanently stored in the storage medium and where the data istemporarily stored in the storage medium.

According to an embodiment, a method according to various embodimentsdisclosed herein may be included and provided in a computer programproduct. The computer program product may be traded as a product betweena seller and a buyer. The computer program product may be distributed inthe form of a machine-readable storage medium (e.g., compact discread-only memory (CD-ROM)), or be distributed (e.g., downloaded oruploaded) online via an application store (e.g., PlayStore™), or betweentwo user devices (e.g., smartphones) directly. If distributed online, atleast part of the computer program product may be temporarily generatedor at least temporarily stored in the machine-readable storage medium,such as a memory of the manufacturer's server, a server of theapplication store, or a relay server.

According to various embodiments, each component (e.g., a module or aprogram) of the above-described components may include a single entityor multiple entities, and some of the multiple entities may beseparately disposed in different components. According to variousembodiments, one or more of the above-described components or operationsmay be omitted, or one or more other components or operations may beadded. Alternatively or additionally, a plurality of components (e.g.,modules or programs) may be integrated into a single component. In sucha case, the integrated component may still perform one or more functionsof each of the plurality of components in the same or similar manner asthey are performed by a corresponding one of the plurality of componentsbefore the integration. According to various embodiments, operationsperformed by the module, the program, or another component may becarried out sequentially, in parallel, repeatedly, or heuristically, orone or more of the operations may be executed in a different order oromitted, or one or more other operations may be added.

While the disclosure has been shown and described with reference tovarious embodiments thereof, it will be understood by those skilled inthe art that various changes in form and details may be made thereinwithout departing from the spirit and scope of the disclosure as definedby the appended claims and their equivalents.

What is claimed is:
 1. An aluminum alloy extruded material comprising:aluminum (Al); zinc (Zn); magnesium (Mg); and copper (Cu), wherein anamount of copper (Cu) and an amount of zinc (Zn) satisfy Equation 1below,[Cu]≥0.14[Zn]−0.782, and wherein [Cu] corresponds to an amount (% byweight (wt %)) of copper (Cu), and [Zn] corresponds to an amount (wt %)of zinc (Zn).
 2. The aluminum alloy extruded material of claim 1,wherein the amount of zinc (Zn) and an amount of magnesium (Mg) satisfyEquation 2 below,${2 \leq \frac{\lbrack{Zn}\rbrack}{\lbrack{Mg}\rbrack} \leq 4},$ andwherein [Zn] corresponds to the amount (wt %) of zinc (Zn), and [Mg]corresponds to an amount (wt %) of magnesium (Mg).
 3. The aluminum alloyextruded material of claim 1, further comprising: an intermetalliccompound including Zn₂Mg, wherein the intermetallic compound has adiameter of 10 micrometers (μm) or less.
 4. The aluminum alloy extrudedmaterial of claim 1, wherein the aluminum alloy extruded materialcomprises crystal grains having an average particle diameter of 100micrometers (μm) to 300 μm, and wherein a potential difference at aninterface between at least two adjacent crystal grains is in a range of30 millivolts (mV) to 100 mV.
 5. The aluminum alloy extruded material ofclaim 1, wherein the zinc (Zn) is present in an amount of 5.85 wt % to8.0 wt %, and wherein the magnesium (Mg) is present in an amount of 2.0wt % to 2.9 wt %.
 6. The aluminum alloy extruded material of claim 1,wherein the copper (Cu) is present in an amount of 0.03 wt % to 0.50 wt%.
 7. The aluminum alloy extruded material of claim 1, wherein theamount of copper (Cu) and the amount of zinc (Zn) satisfy Equation 3below,${0.003 \leq \frac{\lbrack{Cu}\rbrack}{\lbrack{Zn}\rbrack} \leq 0.375},$and wherein [Cu] corresponds to the amount (wt %) of copper (Cu), and[Zn] corresponds to the amount (wt %) of zinc (Zn).
 8. The aluminumalloy extruded material of claim 1, wherein the amount of copper (Cu)and the amount of zinc (Zn) satisfy Equation 4 below,${\frac{\lbrack{Cu}\rbrack}{\lbrack{Zn}\rbrack} \geq {0.14 - \frac{0.782}{\lbrack{Zn}\rbrack}}},$wherein [Cu] corresponds to the amount (wt %) of copper (Cu), and [Zn]corresponds to the amount (wt %) of zinc (Zn).
 9. The aluminum alloyextruded material of claim 1, further comprising: manganese (Mn);silicon (Si); iron (Fe); titanium (Ti); zirconium (Zr); and chromium(Cr), wherein the manganese (Mn) is present in an amount of 0.1 wt % to0.3 wt %, wherein the silicon (Si) is present in an amount of 0.01 wt %to 0.1 wt %, wherein the iron (Fe) is present in an amount of 0.01% to0.15 wt %, wherein the titanium (Ti) is present in an amount of 0.005 wt% to 0.03 wt %, wherein the zirconium (Zr) is present in an amount of0.005 wt % to 0.03 wt %, and wherein the chromium (Cr) is present in anamount of 0.0001 wt % to 0.03 wt %.
 10. The aluminum alloy extrudedmaterial of claim 1, further comprising: manganese (Mn); silicon (Si);iron (Fe); titanium (Ti); zirconium (Zr); and chromium (Cr), wherein thezinc (Zn) is present in an amount of 5.85 wt % to 8.0 wt %, wherein themagnesium (Mg) is present in an amount of 2.0 wt % to 2.9 wt %, whereinthe copper (Cu) is present in an amount of 0.03 wt % to 0.50 wt %,wherein the manganese (Mn) is present in an amount of 0.1 wt % to 0.3 wt%, wherein the silicon (Si) is present in an amount of 0.01 wt % to 0.1wt %, wherein the iron (Fe) is present in an amount of 0.01% to 0.15 wt%, wherein the titanium (Ti) is present in an amount of 0.005 wt % to0.03 wt %, wherein the zirconium (Zr) is present in an amount of 0.005wt % to 0.03 wt %, wherein the chromium (Cr) is present in an amount of0.0001 wt % to 0.03 wt %, and wherein the aluminum (Al) accounts for aremainder of the aluminum alloy extruded material.
 11. The aluminumalloy extruded material of claim 1, wherein the aluminum alloy extrudedmaterial has a yield strength of 450 megapascals (MPa) or greater. 12.The aluminum alloy extruded material of claim 1, wherein the aluminumalloy extruded material has a surface hardness of 150 Vickers hardness(Hv) or greater.
 13. The aluminum alloy extruded material of claim 1,wherein the aluminum alloy extruded material has a surface gloss of 300gloss units (GU) or greater measured according to InternationalOrganization for Standardization (ISO)
 2813. 14. An electronic devicehousing comprising the aluminum alloy extruded material of claim 1.